1. Field of the Invention
The present invention relates generally to electromagnetic and chemical acceleration of projectiles.
2. Description of the Related Art
High velocity metal slugs have a variety of uses, but rather large and complicated facilities, e.g. staged gas guns, are required to produce speeds of over about 1 km/s. Chemical propellants ignite and produce a high pressure gas that pushes metal slugs out of gun barrels. The speed that can be achieved is limited by the speed of sound in the combustion products, which may reach a few thousand degrees Kelvin (K). Speeds nearing 1.2 km/s have been achieved in some prior art systems but are not normally reached. Prior art railguns routinely accelerated projectiles to speeds greater than 1.2 km/s; however, railgun barrel construction is complicated and expensive, and the barrel lifetime is limited. In prior art railgun systems, immense forces push the rails apart, and very strong containment is required; insulators are utilized to separate the conducting rails, and large power supplies are required.
Prior art purely electromagnetic launchers required a large amount of electrical energy to drive the projectiles, and the large amount of electrical energy must be stored at high voltage. Electrical storage combining high energy density, high power density, and high voltage is bulky and heavy. Batteries and electrical double layer capacitors have high energy density but low voltage and limited power density. Chemical energy storage has much higher density than electromagnetic storage but conversion from chemical to electromagnetic energy normally requires significant processing. Electrothermal chemical ((ETC) and electrochemical (EC) guns use chemical energy to accelerate a projectile, but fail to achieve really high slug speeds because they use electromagnetic energy to ignite the propellant but not to accelerate the slug after the chemical propellant has ignited.